Phaceloid rugose coral -- I believe that this is not Palaeophyllum. I have studied several Ordovician species (including the type) and 3 Silurian species of Palaeophyllum and all are characterized by strongly arched tabulae with a marked axial depression. In longitudinal sections they look like this: [drawing of a way line]. In the specimens at hand the tabulae are nearly flat. Further, I suspect (with Charlie) that there is a single row of elongate dissepiments in at least one of the individuals. The specimens are so poorly preserved that they cannot be identified. However, there are some Devonian corals with which they can be compared. Spongophyllum pax Smith, 1945 and S. unperfectum Smith 1945, have closely spaced, nearly flat tabulae, short septa, and a discontinuous, single row of dissepiments. S. pax is closest to the specimens at hand and is supposed to be Middle Devonian. The Middle Devonian Dendrostella rhenana Frech is similar to the Alaska specimens but has a thicker wall and longer? septa. The Alaska specimens don't preserve the key characters but I thinkthat they may be Middle Devonian and that they don't argue against a Middle Devonian age if other evidence is favorable. I have prepared sections of the possible Amphipora. I agree that they cannont be definitely recognized, but feel that they are probable. As you know, I accept Amphipora as indicative of Middle or early Late Devonian age. In summary, this collection contains the following: Amphipora? sp. Phaceloid rugose coral, indeterminate The collection is probably of Middle or early Late Devonian age. This one paragraph can be used or quoted if your wish--my wanderings on what the coral might be are for internal consumption only and must not be quoted. |